Foo Fighters, City of Manchester Stadium, Manchester

'Do you mind," Dave Grohl asks several thousand Mancunians, "if we play some new shit, some old shit, some rock shit, and some acoustic shit?" That's a lot of shit. But the Foo Fighters have a lot of time. "I hope you've had a really big piss," he cautions not long after the start. "It's gonna be a long night."

He's not kidding. Conducting a set-length auction ("1 hour 30? 1 hour 45? All night?"), the winning option is "Play till we can't fuckin' play any more". Crowd-pleasing bonhomie is one of Grohl's fortes. By all accounts the nicest guy in rock, he's certainly one of the smiliest: striding up and down a neon-lit catwalk, when he isn't screaming that raw-throated scream he's grinning that dazzling grin.

He has the demeanour of someone who nothing bad has ever happened to. Which is odd, because we all know of at least one really bad thing that has happened to Dave Grohl (the suicide of a close friend). Maybe that's the reason: he can't let himself "go there". Against his amiability, one must weigh the fact that he's had a hand in the rise of Jack Black. In his favour, he has self-deprecation down to a fine art. After asking who has never seen Foo Fighters before, he responds, "It's a good thing you waited. We used to suck, but we're really good now."

Well, they're good at something. When Nirvana ended and grunge fizzled out, nobody could have predicted that the person who would become a global rock star was the little drummer guy. But there's a reason why they've risen to a somewhat surprising level of mega-popularity. This is Venn diagram rock. Foo Fighters are positioned at the intersections of four groups: people who are into metal; those who are into indie; people who are into emo; and hairdressers and sales reps with very mainstream tastes indeed.

Foo Fighters expertly straddle the Xfm/NME demographic and the Kerrang!/Scuzz demographic, and that's why they're now big enough to be able almost to fill Man City's stadium. It helps that they have scores of songs that you think you recognise when you hear them, but only because they remind you of another Foo Fighters song. Not quite enough, though, to pad out an almost three-hour set.

There are snatches of other people's songs. And, God help us, there are the solos. Then, at last, they get on with it: indistinguishable stadium rock hit after indistinguishable stadium rock hit. In an irony that surely isn't lost on Grohl himself, the loudest moment of the night is thousands of Foo fans chanting, "There goes my hero ... he's ordinary." Sometimes they just gift it to you, these bands.